1. Field of the Invention
This invention relates to a method of and an apparatus for manufacturing a porous static pressure gas bearing in which a porous material is disposed on the surface of a bearing and pressurized gas is injected from vent pores in the porous material into a minute gap between the porous material and a shaft to thereby form gas film and support the shaft, and particularly to a method of and an apparatus for adjusting the flow rate in the porous static pressure gas bearing.
2. Description of the Prior Art
To obtain bearing performances such as predetermined rotation accuracy, load capability and bearing rigidity in a porous gas bearing, it is required that when gas is supplied to a porous material under predetermined pressure, the flow rate of the gas injected per unit area on the surface of the bearing, i.e., the flow rate of passage of the gas, be uniform at a predetermined value over the whole surface of the bearing. As a method of adjusting such a flow rate, it has heretofore been practised to impregnate the surface of the bearing with resin and close pores in the porous material in advance so that the flow rate may be a predetermined rate or below, and thereafter suitably remove the resin by a solvent while measuring the flow rate of passage of the gas, and adjust the flow rate so as to become uniform. This method has involved rubbing the surface of the bearing with an applicator containing a suitable quantity of solvent to thereby dissolve the resin and repetitively effect adjustment while gradually recovering the flow rate.
In the prior art, however, the adjusting work has resorted to the operator's experience or sixth sense and therefore, the adjusting method has suffered from trial and error and has required a great number of working steps which has caused an increase in cost. Also, this method has resorted to manual work and therefore, it has been hard to standardize the work, which in turn has led to great irregularity of quality. Also, when the change-over of the flow rate adjusting surface of a large porous gas bearing is to be effected by manual work, the efficiency of work has been low and dangers have been involved.